Autonomous muting indication to enable improved time difference of arrival measurements

ABSTRACT

A method, a user communication device, and a base station are disclosed. A transceiver  302  may receive a serving transmission from a serving base station. A processor  304  may make a status determination of an autonomous muting status of a neighbor base station based on the serving transmission.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/573,456 entitled “Muting Indication to Enable Improved TimeDifference of Arrival Measurements” by Colin Frank et al. filed on Oct.5, 2009.

TECHNICAL FIELD

The present disclosure relates to a method and system for locating auser communication device in a coordinated network. The presentdisclosure further relates to efficiently mitigating interference fromthe serving cell when determining the position of the user communicationdevice.

BACKGROUND

The Third Generation Partnership Project (3GPP) is developing a LongTerm Evolution (LTE) standard using a physical layer based on globallyapplicable evolved universal terrestrial radio access (E-UTRA). Inrelease-8 specification of LTE, an LTE base station, referred to as anenhanced Node-B (eNB), may use an array of four antennas to broadcast asignal to a piece of user equipment.

A user communication device, or user equipment (UE) device, may rely ona pilot or reference symbol (RS) sent from the transmitter for channelestimation, subsequent data demodulation, and link quality measurementfor reporting. Further, the UE device may rely on a positioningreference symbol (PRS) to determine an observed time difference ofarrival (OTDOA) of the PRS from one or more network base stations. TheUE device may send the OTDOA to the network. The network may use thatdata to calculate the position of the UE device within the network bycalculating the distance of the UE device from the network base stationsof the network and triangulating the position of the UE device.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding that these drawings depict only typical embodiments of thedisclosure and are not therefore to be considered to be limiting of itsscope, the disclosure will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 illustrates in a block diagram one embodiment of a communicationsystem.

FIG. 2 illustrates a possible configuration of a computing system to actas a base transceiver station.

FIG. 3 illustrates, in a block diagram, one embodiment of a mobilesystem or electronic device to create a radio connection.

FIGS. 4 a-b illustrate, in a block diagram, different embodiments of aresource block of a positioning subframe.

FIG. 5 illustrates, in a block diagram, one embodiment of a systeminformation block.

FIG. 6 illustrates, in a block diagram, one embodiment of a positioningassistance data set provided via radio resource control signaling.

FIG. 7 illustrates, in a flowchart, one embodiment of a method forinferring the autonomous muting status of a neighbor base station.

FIG. 8 illustrates, in a flowchart, one embodiment of a method forreceiving an autonomous muting status indication.

FIG. 9 illustrates, in a flowchart, one embodiment of a method formaking a combination time distance of arrival measurement.

FIG. 10 illustrates, in a flowchart, one embodiment of a method forindicating autonomous muting status to a user communication device.

DETAILED DESCRIPTION

Additional features and advantages of the disclosure will be set forthin the description which follows, and in part will be obvious from thedescription, or may be learned by practice of the disclosure. Thefeatures and advantages of the disclosure may be realized and obtainedby means of the instruments and combinations particularly pointed out inthe appended claims. These and other features of the present disclosurewill become more fully apparent from the following description andappended claims, or may be learned by the practice of the disclosure asset forth herein.

Various embodiments are discussed in detail below. While specificimplementations are discussed, it should be understood that this is donefor illustration purposes only. A person skilled in the relevant artwill recognize that other components and configurations may be usedwithout parting from the spirit and scope of the disclosure.

The present disclosure comprises a variety of embodiments, such as amethod, a user communication device, and a network base station, andother embodiments that relate to the basic concepts of the disclosure.The user communication device may be any manner of computer, mobiledevice, or wireless communication device.

A method, a user communication device, and a base station are disclosed.A transceiver may receive a serving transmission from a serving basestation. A processor may make a status determination of an autonomousmuting status of a neighbor base station based on the servingtransmission.

FIG. 1 illustrates one embodiment of a communication network 100. Whilea Long Term Evolution (LTE) carrier communication system 100, as definedby the Third Generation Partnership Project (3GPP®) is disclosed, othertypes of communication systems may use the present disclosure. Variouscommunication devices may exchange data or information through thenetwork 100. The network 100 may be an evolved universal terrestrialradio access (E-UTRA), or other type of telecommunication network.

A LTE user equipment (UE) device 102, or user communication device, mayaccess the coordinated communication network 100 via any one of a numberof LTE network base stations, or enhance Node Bs (eNB), that support thenetwork. For one embodiment, the UE device 102 may be one of severaltypes of handheld or mobile devices, such as, a mobile phone, a laptop,or a personal digital assistant (PDA). For one embodiment, the UE device102 may be a WiFi® capable device, a WiMAX® capable device, or otherwireless devices.

The primary network base station currently connecting the UE device 102to the coordinated communications network may be referred to as aserving base station 104. The UE device 102 may receive signals fromother network base stations proximate to the serving base station 104,referred to herein as a neighbor base station 106.

A cellular site may have multiple base stations. A cellular site havingthe serving base station 104 may be referred to herein as the servingsite 108. A cellular site that does not have the serving base station104 may be referred to herein as the neighbor site 110. A serving site108 may also have one or more neighbor base stations in addition to theserving network base station 108, referred to herein as a serving siteneighbor base station 112.

The coordinated communication network 100 may use a location server 114to triangulate the network location of the UE device 102 within thecoordinated communication network 100. Alternatively, one of the basestations may act as a location server 114. Each base station maybroadcast a positioning reference transmission to be received by the UEdevice 102. The location server 114 may use the positioning referencetransmission to determine the location of the UE device 102 within thenetwork 100. Alternately, the UE device 102 or the serving base station104 may use the positioning reference transmission to determine thelocation. The positioning reference transmission may be a set of one ormore positioning reference symbols (PRS) of various values arranged in apattern unique to the base station sending the positioning referencetransmission.

The positioning reference transmission from the serving base station 104may be referred to herein as the serving positioning referencetransmission (SPRT) 116. The positioning reference transmission from theneighbor base station 106 may be referred to herein as the neighborpositioning reference transmission (NPRT) 118. The positioning referencetransmission from the serving site neighbor base station 112 may bereferred to herein as a same site positioning reference transmission(SSPRT) 120. The UE device 102 may measure the observed time differenceof arrival (OTDOA) for each NPRT 118, to determine the distance betweenthe UE device 102 and each observed neighbor base station 106.

FIG. 2 illustrates a possible configuration of a computing system 200 toact as a network operator server 106 or a home network base station 110.The computing system 200 may include a controller/processor 210, amemory 220, a database interface 230, a transceiver 240, input/output(I/O) device interface 250, and a network interface 260, connectedthrough bus 270. The network server 200 may implement any operatingsystem. Client and server software may be written in any programminglanguage, such as C, C++, Java or Visual Basic, for example. The serversoftware may run on an application framework, such as, for example, aJava® server or .NET® framework

The controller/processor 210 may be any programmed processor known toone of skill in the art. However, the method may also be implemented ona general-purpose or a special purpose computer, a programmedmicroprocessor or microcontroller, peripheral integrated circuitelements, an application-specific integrated circuit or other integratedcircuits, hardware/electronic logic circuits, such as a discrete elementcircuit, a programmable logic device, such as a programmable logicarray, field programmable gate-array, or the like. In general, anydevice or devices capable of implementing the method as described hereinmay be used to implement the system functions of this disclosure.

The memory 220 may include volatile and nonvolatile data storage,including one or more electrical, magnetic or optical memories such as arandom access memory (RAM), cache, hard drive, or other memory device.The memory may have a cache to speed access to specific data. The memory220 may also be connected to a compact disc-read only memory (CD-ROM),digital video disc-read only memory (DVD-ROM), DVD read write input,tape drive, or other removable memory device that allows media contentto be directly uploaded into the system.

Data may be stored in the memory or in a separate database. The databaseinterface 230 may be used by the controller/processor 210 to access thedatabase. The database may contain a subscriber information set for eachUE device 102 that may access the network 100, as well as a physicalcell identifier (PCID) for the base station.

The transceiver 240 may create a connection with the mobile device 104.The transceiver 240 may be incorporated into a base station 200 or maybe a separate device.

The I/O device interface 250 may be connected to one or more inputdevices that may include a keyboard, mouse, pen-operated touch screen ormonitor, voice-recognition device, or any other device that acceptsinput. The I/O device interface 250 may also be connected to one or moreoutput devices, such as a monitor, printer, disk drive, speakers, or anyother device provided to output data. The I/O device interface 250 mayreceive a data task or connection criteria from a network administrator.

The network connection interface 260 may be connected to a communicationdevice, modem, network interface card, a transceiver, or any otherdevice capable of transmitting and receiving signals from the network.The network connection interface 260 may be used to connect a clientdevice to a network. The network interface 260 may connect the homenetwork base station 110 to a mobility management entity of the networkoperator server 106. The components of the network server 200 may beconnected via an electrical bus 270, for example, or linked wirelessly.

Client software and databases may be accessed by thecontroller/processor 210 from memory 220, and may include, for example,database applications, word processing applications, as well ascomponents that embody the functionality of the present disclosure. Thenetwork server 200 may implement any operating system. Client and serversoftware may be written in any programming language. Although notrequired, the disclosure is described, at least in part, in the generalcontext of computer-executable instructions, such as program modules,being executed by the electronic device, such as a general purposecomputer. Generally, program modules include routine programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types. Moreover, those skilled in theart will appreciate that other embodiments of the disclosure may bepracticed in network computing environments with many types of computersystem configurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike.

FIG. 3 illustrates one embodiment of a mobile device 300, capable ofacting as a UE device 102 or user communication device. For someembodiments of the present disclosure, the mobile device 300 may alsosupport one or more applications for performing various communicationswith a network. The mobile device 300 may be a handheld device, such as,a mobile phone, a laptop, or a personal digital assistant (PDA). Forsome embodiments of the present disclosure, the user device 300 may beWiFi® capable device, which may be used to access the network mobile fordata or by voice using VOIP.

The mobile device 300 may include a transceiver 302, which is capable ofsending and receiving data over the mobile network 102. The mobiledevice 300 may include a processor 304 that executes stored programs.The mobile device 300 may also include a volatile memory 306 and anon-volatile memory 308 to act as data storage for the processor 304.The mobile device 300 may include a user input interface 310 that maycomprise elements such as a keypad, display, touch screen, and the like.The mobile device 300 may also include a user output device that maycomprise a display screen and an audio interface 312 that may compriseelements such as a microphone, earphone, and speaker. The mobile device300 also may include a component interface 314 to which additionalelements may be attached, for example, a universal serial bus (USB)interface. Finally, the mobile device 300 may include a power supply316.

In order to determine the position of the UE device 102 within thecoordinated communication network 100, the UE device 102 may maketime-difference-of-arrival measurements on the neighboring network basestations 106. The UE device 102 may use positioning subframes andpositioning reference symbols to better “hear” neighbor base stations106.

As each base station sends a different positioning referencetransmission, the positioning reference symbols may become interlaced inthe frequency domain. Each base station may apply one of a set offrequency offsets, for example a set of six frequency offsets, to betterdistinguish between the base stations. As a coordinated communicationnetwork 100 may have more base stations than frequency offsets, multiplebase stations may be assigned the same offset. For example, if thenetwork 100 has eighteen base stations and uses six frequency offsets,each frequency offset may be assigned to three base stations.

Depending on the bandwidth of the system, the positioning subframe maycontain any number of resource blocks, such as six to one hundredresource blocks. The resource block may have, for example, twelve tofourteen symbols and twelve subcarriers. For a largest bandwidth of 20MHz, the positioning subframe may have, for example, one hundredresource blocks, and thus 1200 subcarriers per subframe. The resourceblocks may be stacked in frequency. Thus, for every symbol within thesubframe, the subframe may have, for example, 1200 subcarriers.

A set of diagonal PRS patterns may be defined for use in the positioningsubframes. The patterns may be frequency offsets of a base diagonalpattern with the cell-specific frequency shift given byv_(shift)=N_(Cell) ^(ID) mod 6.

Different resource blocks may represent different base stations. FIG. 4a may illustrate, in a block diagram, one embodiment of a resource block400 from a first base station, while FIG. 4 b may illustrate, in a blockdiagram, one embodiment of a resource block 410 from a second basestation. The positioning subframe may have both a time component and afrequency component. Each resource block 400 may begin with a set ofcontrol region symbols 402. The resource block 400 may have a commonreference symbol representing an antenna port. One or more positioningreference symbols 406 may be encoded in the positioning subframe in apattern. A UE device may use both the pattern and the values of thepositioning reference symbols 406 to identify the originating basestation.

Even with the inclusion of positioning reference symbols 406, a UEdevice 102 near a serving base station 104 may have significantdifficulty in measuring the OTDOA of a neighbor base station 106 formultiple reasons. One reason may be the adaptive gain control or analogto digital converter limitations in the receiver. If the UE device isnear the serving base station 104, the power of the serving base station104 may far exceed that of the neighbor base station to be measured. Asa result of these dynamic range limitations in the UE device 102, the UEdevice 102 may not be able to take measurements on a sufficient numberof neighbor base stations 106 to enable an accurate position fix.

A second reason may be the misalignment of the positioning referencesymbol (PRS) pattern. The PRS patterns may be orthogonal in thefrequency domain. However, if two base stations are assigned orthogonalPRS patterns, the orthogonal nature of the corresponding positioningreference transmission signals received by the UE device 102 may dependon the positioning reference transmission signals being properly alignedas observed by the UE device 102. The positioning reference transmissionsignals may be considered properly aligned if the sum of the OTDOA andthe channel delay spread do not exceed the cyclic prefix. Otherwise, thepositioning reference transmission signals received by the UE device 102may not be orthogonal even if the PRS patterns are. If a neighbor basestation 106 is assigned a different pattern than the serving basestation 104, the UE device 102 may make an OTDOA measurement on theneighbor base station 106 without interference from the serving basestation 104, assuming no adaptive gain control or analog to digitalconverter limitations. However, if the sum of the OTDOA and the channeldelay spread exceed the channel cyclic prefix, the OTDOA measurementsmay be contaminated with interference from the serving base station,which may be very strong when the UE device 102 is near the serving basestation 104.

In a partially synchronous network, the positioning subframes fromdifferent base stations may be offset by as much as one-half a subframeor more, resulting in misalignment of the symbol boundaries. Thus, thePRS patterns which are orthogonal in the frequency domain when thepositioning subframes are time aligned may no longer be orthogonal,regardless of the channel delay-spread or the OTDOA of the serving basestation 104 and the neighbor base stations 106.

One solution to the above problems is to sometimes mute the serving basestation 104 in order to enable the UE device 102 to take accurate OTDOAmeasurements on a sufficient number of neighbor base stations 106 whenthe UE device 102 is near the serving base station 104.

The base station may transmit the positioning reference transmissionwith zero power in certain positioning subframes, or mute certainpositioning subframes. However, the UE device 102 may currently beunaware of whether or not a particular base station has muted itspositioning reference transmission, leading to problems when thepositioning reference transmission from a neighbour base station 106 issufficiently weak to prevent a reliable determination of whether or notthe positioning reference transmission were transmitted by a particularbase station, and thus whether or not the OTDOA measurement for the basestation is valid.

A base station may perform this muting of the position referencetransmission autonomously. Referring back to FIG. 1, a neighbor site 110that allows one of its base stations to autonomously mute the positionreference transmission may be referred to herein as an autonomousneighbor site 122. A base station on an autonomous neighbor site 122 maybe referred to as an autonomous base station 124. The position referencetransmission sent by the autonomous base station 124 may be referred toas an autonomous position reference transmission (APRT) 126. Similarly,a scheduled neighbor site 128 may forgo muting or may mute the positionreference transmission following a scheduled pattern known to the UEdevice 102. A base station on a scheduled neighbor site 128 may bereferred to as a scheduled base station 130. The position referencetransmission sent by the scheduled base station 130 may be referred toas a scheduled position reference transmission (SCPRT) 132.

The serving base station 104 may explicitly alert the UE device 102 thatthe serving base station 104 or other base stations in the mobilenetwork may perform autonomous muting. Thus, the UE device 102 may knowin advance to perform a muting threshold test to distinguish between anactual position reference transmission and noise. The serving basestation 104 may send an autonomous muting status indication in a systeminformation block (SIB) or in a position assistance data set of a radioresource control signal. The autonomous muting status indication may bea network autonomous muting status indication that references an entiremobile network or sub-network. Additionally, the autonomous mutingstatus indication may be a station autonomous muting status indicationthat references just the neighbor base station.

FIG. 5 illustrates, in a block diagram, one embodiment of a SIB 500. Theserving base station 104 may send the SIB 500 to the UE device 102 sothat the UE device 102 may properly interpret the positioning data. TheSIB 500 may have a header 502 identifying the SIB 500. The SIB 500 mayhave a transmission time 504 for the set of positioning subframes. TheSIB 500 may have a neighbor station search offset 506, giving the UEdevice 102 a window to search for neighbor base stations 106. The SIB500 may have a network autonomous muting status indication 508 thatalerts the UE device 102 that a base station in the mobile network mayautonomously control its own muting. In some instances, the SIB 500 maycontain a list 510 of PCIDs of neighbor base stations 106 for whichOTDOA may be taken.

FIG. 6 illustrates, in a block diagram, one embodiment of a positioningassistance data set 600 for a radio resource control signal. The servingbase station 104 may send the positioning assistance data set 600 to theUE device 102 so that the UE device 102 may properly interpret thepositioning data. The positioning assistance data set 600 may have aheader 602 identifying the positioning assistance data set 600. Thepositioning assistance data set 600 may have a transmission time 604 forthe set of positioning subframes. The positioning assistance data set600 may have a neighbor station search offset 606. The positioningassistance data set 600 may have a network autonomous muting statusindication 608 that alerts the UE device 102 that a base station in themobile network may autonomously control its own muting. In someinstances, the positioning assistance data set 600 may contain a list610 of PCIDs of neighbor base stations 106 for which OTDOA may be taken.The PCID list 610 may further contain an individual station autonomousmuting status indication 612 paired with each PCID 614 representing eachneighbor base station 106 that has an autonomous muting status thatdiffers from the overall network.

The UE device 102 may make a status determination of an autonomousmuting status of a neighbor base station 106 based on the servingtransmission, even if no affirmative autonomous muting status indicationis encoded in the serving transmission. Generally, a synchronous networkmay not allow autonomous muting and an asynchronous network may allowautonomous muting. The UE device may infer from a small neighbor stationsearch offset that a mobile network is a synchronous network, while alarge neighbor station search offset may indicate an asynchronousnetwork.

FIG. 7 illustrates one embodiment of a method 700 for inferring theautonomous muting status of a neighbor base station. The UE device 102may receive a serving transmission from a serving base station 104(Block 702). The UE device 102 may decode a neighbor station searchoffset from the serving transmission (Block 704). The UE device 102 mayapply a configuration threshold test to the neighbor base station searchoffset to make a configuration determination of whether the mobilenetwork is a synchronous network or an asynchronous network (Block 706).If the search offset is greater than the configuration threshold (Block708), then the UE device 102 may designate the mobile network 100 as anasynchronous network (Block 710). The UE device may infer that theautonomous muting status is active for the neighbor base station 106(Block 712). Thus the neighbor base station 106 may autonomously controlits own muting. If the search offset is not greater than theconfiguration threshold (Block 708), then the UE device 102 maydesignate the mobile network 100 as an synchronous network (Block 714).The UE device may infer that the autonomous muting status is inactivefor the neighbor base station 106 (Block 712). Thus the location serveror a network operator may control the muting of the neighbor basestation 106.

FIG. 8 illustrates one embodiment of a method 800 for receiving anautonomous muting status indication. The UE device 102 may receive aserving transmission from a serving base station 104 (Block 802). The UEdevice 102 may decode an autonomous muting status indication from theserving transmission (Block 804). The autonomous muting statusindication may be a network autonomous muting status indication or astation autonomous muting status indication. If the autonomous mutingstatus indication labels the status as active (Block 806), then the UEdevice 102 may designate the autonomous muting status as active for theneighbor base station 106 (Block 808). If the autonomous muting statusindication labels the status as inactive (Block 806), then the UE device102 may designate the autonomous muting status as inactive for theneighbor base station 106 (Block 810).

Once the UE device 102 has determined the autonomous muting status for aneighbor base station 106, the UE device 102 may take a neighbor basestation status reading for purposes of determining position within thenetwork. FIG. 9 illustrates one embodiment of a method 900 for making acombination time distance of arrival measurement. The UE device 102 mayreceive a neighbor base station reading (Block 902). If the autonomousmuting status is inactive (Block 904), then the UE device 102 maycombine the neighbor base station reading into a position measurement(Block 906). If the autonomous muting status is active (Block 904), thenthe UE device 102 may apply a muting threshold test to the neighbor basestation reading (Block 908). If the neighbor base station reading doesnot exceed a muting threshold (Block 910), then the UE device 102 maydiscard the neighbor base station reading as noise (Block 912). If theneighbor base station reading exceeds a muting threshold (Block 910),then the UE device 102 may combine the neighbor base station readinginto a position measurement (Block 906). The UE device 102 may send theposition measurement to the serving base station 104 (Block 914).Alternatively, the UE device 102 may forward a neighbor base stationreading that exceeds the muting threshold to the serving base station104. The serving base station 104 may combine the neighbor base stationreading into a position measurement or forward the neighbor base stationreading to the location server 114.

FIG. 10 illustrates one embodiment of a method 1000 for indicatingautonomous muting status to a user communication device 102. The servingbase station 104 may determine the muting status of the mobile network(Block 1002). The serving base 104 station may determine any anomalousstation muting statuses that may affect positioning readings (Block1004). The serving base station 104 may encode the serving transmissionwith the network autonomous muting status indication and the stationautonomous muting status indication (Block 1006). The serving station104 may send the serving transmission to the UE device 102 (Block 1008).The serving station 104 may receive a position measurement from the UEdevice 102 (Block 1010). The serving base station 104 may forward theposition measurement on to the location server 114 (Block 1012).Alternatively, the serving base station 104 may receive a neighbor basestation reading from the UE device. The serving base station 104 maycombine the neighbor base station reading into a position measurement orforward the neighbor base station reading to the location server 114.

Embodiments within the scope of the present disclosure may also includecomputer-readable media for carrying or having computer-executableinstructions or data structures stored thereon. Such computer-readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium which can be used to carryor store desired program code means in the form of computer-executableinstructions or data structures. When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or combination thereof) to a computer, the computerproperly views the connection as a computer-readable medium. Thus, anysuch connection is properly termed a computer-readable medium.Combinations of the above should also be included within the scope ofthe computer-readable media.

Embodiments may also be practiced in distributed computing environmentswhere tasks are performed by local and remote processing devices thatare linked (either by hardwired links, wireless links, or by acombination thereof) through a communications network.

Computer-executable instructions include, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions. Computer-executable instructions also includeprogram modules that are executed by computers in stand-alone or networkenvironments. Generally, program modules include routines, programs,objects, components, and data structures, etc. that perform particulartasks or implement particular abstract data types. Computer-executableinstructions, associated data structures, and program modules representexamples of the program code means for executing steps of the methodsdisclosed herein. The particular sequence of such executableinstructions or associated data structures represents examples ofcorresponding acts for implementing the functions described in suchsteps.

Although the above description may contain specific details, they shouldnot be construed as limiting the claims in any way. Other configurationsof the described embodiments of the disclosure are part of the scope ofthis disclosure. For example, the principles of the disclosure may beapplied to each individual user where each user may individually deploysuch a system. This enables each user to utilize the benefits of thedisclosure even if any one of the large number of possible applicationsdo not need the functionality described herein. In other words, theremay be multiple instances of the electronic devices each processing thecontent in various possible ways. It does not necessarily need to be onesystem used by all end users. Accordingly, the appended claims and theirlegal equivalents should only define the disclosure, rather than anyspecific examples given.

We claim:
 1. A method for measuring a time difference of arrivalmeasurement in a mobile device, comprising: receiving a muting statusindication in a position assistance data from a serving base station,wherein the position assistance data includes at least a physical cellidentifier corresponding to a neighbor base station, a muting statusapplicable to a positioning reference signal transmission from theneighbor base station, and a neighbor cell search offset applicable to apositioning reference signal transmission from the neighbor basestation; making a status determination of a muting status of a neighborbase station, where the status determination includes inferring that themuting status is inactive based on the received muting statusindication; receiving a positioning reference signal transmitted fromthe neighbor base station; and determining a time difference of arrivalof the neighbor base station transmission based on the receivedpositioning reference signal and based on the muting status.
 2. Anapparatus for measuring a time difference of arrival measurement in amobile equipment, comprising: a receiver that receives a muting statusindication in a positioning assistance data from a serving base station,wherein the positioning assistance data includes at least a physicalcell identifier corresponding to a neighbor base station, a mutingstatus applicable to a positioning reference signal transmission fromthe neighbor base station, and a neighbor cell search offset applicableto a positioning reference signal transmission from the neighbor basestation; and a processor coupled to the receiver, the processorconfigured to make a status determination of a muting status of aneighbor base station, where the status determination includes inferringthat the muting status is inactive based on the received muting statusindication, wherein the receiver is further configured to receive apositioning reference signal transmitted from the neighbor base station;and wherein the processor is further configured to determine a timedifference of arrival of the neighbor base station transmission based onthe received positioning reference signal and the muting status.